Machines for cutting sheet material such as fabric, cloth, vinyl, leather and the like typically have a work material supporting bed comprising a plurality of generally vertically extending bristles. Upper free ends of the bristles define a work material supporting surface so that the bed may be penetrated by a cutting tool such as a reciprocating knife, a rotating drill, or the like that is used to cut the sheet material. As shown in FIG. 1, one or more sheets 1 of the work material 2 to be cut are typically stacked on the supporting surface 3 and air 4 is passed downwardly through the bed 5 to create vacuum pressure at the supporting surface 4 which holds and compresses the work material 2 in position. If needed the work material 2 is covered with a layer of air impervious material 6 to create the vacuum pressure. Cutting debris 7 tends to collect between the bristles 8 of the bed 5 and should be removed to maintain efficient performance of the machine. The debris 7 can hinder operation of the cutting tool and/or impede air flow through the bed 5.
One method of cleaning the debris from the bristles has been to periodically remove the bristle bed from the machine, such as between work shifts. Bed portions are placed in a cleaning apparatus which removes debris. One such apparatus cleans the bed portions by applying sharp impact forces to the bed portions to shake the accumulated debris from the bristles. For examples of such cleaning apparatus see U.S. Pat. Nos. 4,224,711 and 5,065,469, the disclosures of which are expressly incorporated herein in their entirety by reference. These cleaning apparatus have the disadvantage that to achieve cleaning of the bristle bed, bristle units must be separated from the cutting machine, cleaned by the cleaning apparatus remote from the cutting machine, and reassembled with the cutting machine. This process requires a great deal of time and labor.
Attempts have been made to provide a cleaner capable of cleaning the bristle bed while the bristle bed remains assembled to the cutting machine. One such cleaner includes a plurality of rotary blades and a vibrator to dislodge the debris and a vacuum device to remove dislodged debris. The cleaner replaces the cutting tool on a cutter carriage or is carried by its own carriage. See U.S. Pat. No. 5,361,453, the disclosure of which is expressly incorporated herein in its entirety by reference. Another such cleaner is for a conveyer-type cutting machine and includes pins at an underside of the conveyer that comb the bristles and a vacuum device to remove dislodged debris. The vacuum system for the bed is diverted to the cleaner during cleaning. See U.S. Pat. No. 5,412,836, the disclosure of which is expressly incorporated herein in its entirety by reference. While these cleaners may be capable of cleaning the bristle bed while the bristle bed remains assembled to the cutting machine, they require the cutting machine to be in a down condition.
Attempts have been made to provide a cleaner for cleaning the bristle bed while the cutting machine remains operational. One such cleaner is for a conveyor type cutting machine and delivers jets of compressed air to dislodge debris at an underside of the conveyor so that the debris falls down to the ground. See U.S. Pat. No. 6,058,556, the disclosure of which is expressly incorporated herein in its entirety by reference. Another such cleaner is also for a conveyor type cutting machine but uses a vacuum device to remove debris. See U.S. Pat. No. 6,732,854, the disclosure of which is expressly incorporated herein in its entirety by reference. While these cleaners may be capable of cleaning the bristle bed while the cutting machine remains operational, they essentially clean portions of the conveyor-type bristle bed while they are “off-line.” Thus, these cleaners cannot be utilized with non-conveyor type cutting machines. Additionally, debris is not removed until cutting of that portion of the work material is complete. Thus, cutting operations subsequent to initial cutting operations on a particular sheet of work material may be affected by debris created by prior cutting operations.
There is a desire to cut work material with a “zero buffer”, that is, without a gap between the end products. A zero buffer results in less wasted work material and thus decreases costs for the end products. To obtain a zero buffer, however, the work material must be precisely positioned and held in place with even vacuum pressure and operation of the cutting tools cannot be hindered by cutting debris. Accordingly, there is a need in the art for an improved sheet material cutting machine which can remove cutting debris as the work material is cut.